This study aims to determine: 1) whether a 4-hour IV infusion of 3 ug/kg/h rhIGF-I will suppress GH secretion in type I diabetics as in normal subjects; 2) the time to onset and recovery from this suppression if it occurs; and 3) relationship of GH suppression to changes in total and free IGF-I levels. Nine type I diabetics (3 men, 6 women) have completed the study. No more admissions are planned and final assay and analyses are pending. Circulating GH levels are increased, and IGF-i levels decreased in this population. The elevated GH levels may aid development of diabetic microvascular complications. A total of 9 subjects completed study with this lower IGF-I dose.